A known torque fluctuation absorber is provided, for example, on a power transmission passage between an engine and a transmission, and absorbs (restrains) torque fluctuations generated by the engine and the transmission. The known torque fluctuation absorber includes, for example, a damper portion that absorbs the torque fluctuations by means of a spring force, a hysteresis portion that absorbs the torque fluctuations by means of a hysteresis torque generated by friction or the like, and a limiter portion that generates slippage when a torsion between respective rotating shafts of the engine and the transmission is beyond absorption capabilities of the damper portion and the hysteresis portion. At the damper portion, a coil spring is arranged on the power transmission passage between a rotating member of an input side and a rotating member of an output side, and seat members are arranged between the coil spring and the rotating member of the input side, and between the coil spring and the rotating member of the output side. In addition, the damper portion includes a stopper portion for restricting a torsion at the damper portion at a predetermined angle in order to protect the coil spring. At the stopper portion, a protrusion provided at the rotating member of the input side of the damper portion and a protrusion provided at the rotating member of the output side of the damper portion come into contact with each other, thereby restricting the torsion at the damper portion. In addition, at the damper portion, a cushion member is arranged at an inside of the coil spring so as to absorb an impact generated when the protrusions come into contact with each other at the stopper portion. In a case where the torsion occurs at the damper portion, the cushion member comes to be sandwiched between seat members each arranged at an end portion of the coil spring before the protrusions of the stopper portion come into contact with each other. Thus, the cushion member absorbs the impact generated when the protrusions of the stopper portion come into contact with each other. A known cushion member 126 (refer to FIG. 17), where abrasion resistant members 131, 133 (resin seats) are adhered to end portions of an elastic member 132 (rubber) is disclosed, for example, in JPH3-26341Y (hereinafter referred to as Patent reference 1) and in JPH5-34343Y (hereinafter referred to as Patent reference 2).
However, the known cushion member 126 is subject to a restriction in a lengthwise direction, in addition, a restriction is imposed in order to assure a dimension of each of the plural abrasion resistant members in the lengthwise direction thereof (because the abrasion resistant members are arranged in-line). Thus, a length of the elastic member 132 may be set to be short. As a result, an amount of stroke is small and an amount of impact absorbed is also small.
Further, according to the known cushion member 126, the elastic member 132 is joined to the abrasion resistant members 131, 133 by means of an adhesive joining. Thus, an adhesive strength may restrict the amount of stroke from increasing, which further reduces a shock absorbing ability. Still further, the elastic member 132 and the abrasion resistant members 131, 133 are joined with one another by means of the adhesive joining, which increases a production cost.
A need thus exists for a torque fluctuation absorber which is not susceptible to the drawback mentioned above.